GB629473A - Metallized azomethine dyes and nylon dyed therewith - Google Patents

Abstract

Nylon is dyed using hot aqueous solutions of azomethine dyes containing cobalt in complex combination, which are free from sulphonic groups and have the formula <FORM:0629473/IV (c)/1> where R is a benzene radical having at least one nitro group, and R1 is a benzene or naphthalene radical which may be unsubstituted or may contain monovalent substituents such as nitro, halogen, amino, alkyl, alkoxy, hydroxy, or cyano. These dyestuffs are obtained by condensing an aromatic ortho-hydroxy amino compound of the benzene or naphthalene series with an ortho-hydroxy benzaldehyde substituted in the nucleus by one or more nitro groups, and heating the resulting azomethine dye, preferably after separation from the reaction mixture, with a solution of a salt of bivalent cobalt. Solvents for this reaction are water, alcohols, acetone, or esters. The cobalt compound may be added with the orthohydroxy-amino compound. Reactants specified are 2-aminophenol, 4-chloro-2-aminophenol, 2 - amino - 4.6 - dichlorophenol, 4 - or 5 - nitro-2 - aminophenol, 3 - amino - p - cresol, 4-aminoresorcin - 1 - methylether, 2 - aminoresorcinol, 6 - amino - 2 - cyanphenol, 2 - amino-1 - naphthol, and 2 - amino - 1.4 - dihydroxynaphthalene. The dyeing solutions may be acid or neutral and may contain surface-active agents and assistants such as ammonium chloride or sodium sulphate. In examples: 5-nitrosalicylaldehyde is reacted with (1) 2-aminophenol; (2) 4-chloro-2-aminophenol; (3) 4 - nitro - 2 - aminophenol; (4) 2 - amino-4.6 - dichlorophenol and the product is treated with ammonia and cobaltous chloride. Also, (5) 5-nitro-2-aminophenol is treated with cobaltous chloride in ethanol and then with 3-nitrosalicylaldehyde. An example of dyeing nylon with the product of (1) is given.